The concession/refutation paragraph comes after the body paragraphs and before the conclusion in an argumentative essay. In constructing this paragraph, you will concede a point or two to the opposition (those who disagree with you) to show that you are a reasonable person and that you understand their position, but then you will refute the general premise and come back even stronger, as you move into your concluding paragraph.
Consider your own topic. What do those who disagree with your position have to say? What is valid about their concerns? How do they miss the point? What can you say to persuade them to consider your point of view?
With the concession/refutation paragraph, you show that you are a reasonable, thoughtful person who understands the various sides of the argument, but you also show that in the end your stance is still the best approach to the issue